Field of the Invention
The present invention relates to a liquid discharge head used for a liquid discharge apparatus, such as an inkjet printing apparatus, that discharges a liquid, such as ink, to perform image formation and printing.
Description of the Related Art
Conventionally, as an element that generates energy for discharging a liquid such as ink, there has been known a liquid discharge head provided with an electrothermal conversion element such as a heater, a piezoelectric element formed using a piezoelectric material, or the like.
In FIG. 7, shown is a partial cross-sectional view of a typical liquid discharge head that uses an electrothermal conversion element as an energy generating element. This liquid discharge head has an Si (silicon) substrate 11 in which a liquid supply port 16 is formed and on which an energy generating element 3 is provided, and a flow path forming member 15 provided on the Si substrate 11. Between the flow path forming member 15 and the Si substrate 11, there are formed a plurality of pressure chambers 14 including the energy generating element 3 and being aligned substantially at regular intervals, and a flow path 17 that causes the respective pressure chamber 14 and the liquid supply port 16 to communicate with each other. In the flow path forming member 15, a discharge port 9 that causes the respective pressure chamber 14 and an outer space to communicate with each other is formed at a position facing the energy generating element 3 of the respective pressure chamber 14. The energy generating element 3 is driven by, for example, an electric circuit or the like that is provided at the liquid discharge head, using a semiconductor manufacturing technology.
In the liquid discharge head with such a configuration, in the case where ink is supplied from the liquid supply port 16 to the flow path 17, it is sent to the pressure chamber 14 through the flow path 17. Subsequently, ink close to the energy generating element 3 bubbles by being instantaneously heated and boiled due to drive of the energy generating element 3, and ink close to the discharge port 9 is discharged from the discharge port 9 by a bubble pressure.
Incidentally, a flow path forming member may peel off from an Si substrate because of stress applied due to flowing of ink through a flow path and a pressure chamber, swelling of the flow path forming member due to soaking of a solvent component of the ink, and the like. In the case where the flow path forming member peels off from the Si substrate, a portion of the flow path forming member having peeled off from the Si substrate prevents an ink flow, a discharge property of the ink changes, and an undesirable effect on image formation may be caused.
There has been known a configuration in which, in order to suppress peeling-off of the flow path forming member from the Si substrate, an interlayer formed of thermoplastic resin which has adhesiveness to the Si substrate higher than the flow path forming member and which can hold the flow path forming member is interposed between the Si substrate and the flow path forming member. For example, FIG. 5A in Japanese Patent Laid-Open No. 2007-230132 discloses a configuration as a nozzle 7B in which an interlayer is laid at a position other than a portion corresponding to a pressure chamber on an Si substrate, that is, so as to surround an energy generating element while avoiding an upper surface of the energy generating element.